Automatic-exposure-programming apparatus for a camera

ABSTRACT

Apparatus for automatically establishing the exposures in halftone screen photography in which a control unit is set to indicate one of a discrete number of highlight densities, and a second setting is set to one of a discrete number of shadow densities and in which the settings control, remotely, a master timing unit to establish the proper exposures. A control unit allows the various exposures to be made after the master timer has been set. The settings are obtained and stored mechanically and then, at the operator&#39;&#39;s convenience and, if desirable, at a relatively remote location, are used as a computer input; the computer is the part of the device which then converts this input (after conversion into electrical form) into an output which represents exposure time intervals which, in turn, control camera operation.

United States Patent Inventors Leonard S. Florsheim, Jr.

Lake Forest, 111.; Harold B. Archer, Henrietta; Philip F. Lo

Presti, Henrietta; Thurlow J. Sutherland,

Rochester, N.Y.

Appl. No. 786,280

Filed Dec. 23, 1968 Patented Oct. 5, 1971 Assignee Robertson Photo-Meehanix, Inc.

Des Plaines, 111.

AUTOMATlC-EXPOSURIB-PROGRAMMING APPARATUS FOR A CAMERA 14 Claims, 10 Drawing Figs.

US. Cl 328/129, /10 R, 235/184, 250/214 P, 307/293, 355/69 Int. Cl G0lr29/02, 1-103k 5/00, G03b 27/76 Field of Search 307/293; 328/129, 271; 250/214 P; 355/35, 69,

356/202; 95/10 A, 10 C, 10 R;235/184,

Primary Examiner-Stanley D. Miller, Jr. Attorney-Hill, Sherman, Meroni, Gross & Simpson ABSTRACT: Apparatus for automatically establishing the exposures in halftone screen photography in which a control unit is set to indicate one of a discrete number of highlight densities, and a second setting is set to one of a discrete number of shadow densities and in which the settings control, remotely, a master timing unit to establish the proper exposures. A control unit allows the various exposures to be made after the master timer has been set. The settings are obtained and stored mechanically and then, at the operator's convenience and, if desirable, at a relatively remote location, are used as a computer input; the computer is the part of the device which then converts this input (after conversion into electrical form) into an output which represents exposure time intervals which, in turn, control camera operation.

IN VLiN TORS SHEET l UF 6 PATENTED 0m 5 I97] leeward 5F M; f w

W) WM 7 ATTORAEYS PATENTED [1m 5 1971 SHEET 6 0F 6 Zsazzaza [hag d AUTOMATIC-EXPOSURE-PROGRAMMING APPARATUS FOR A CAMERA BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to photography and in particular to automatic apparatus that allows various exposures to be set automatically.

2. Description of the Prior Art In half-tone photography images are converted to dots of different sizes. There are three separate exposures of a fllm which are made during the production of a half-tone. These are the highlight bump exposure which is through the lens to the image without a half-tone screen. The main exposure is through the lens to the subject with the half-tone screen in place. The third exposure is the flash exposure in which the photographic film is exposed to nonimage light directly and is not necessarily a through-the-lens exposure. The times for these three exposures are normally calculated by measuring the highlight density and the shadow density of the copy, and then calculating the various exposures from these measurements. The difference between highlight and shadow densities is called the density range.

The density range of the copy decreased by a fixed quantity, which is dependent upon camera, screen, film and other conditions, determines the excess density range. The excess density range detennines the time for the flash exposure and the highlight density determines the time for the main exposure. The highlight exposure is often expressed as a percentage of the main exposure. In the prior art the highlight density and the shadow density have been measured and the various exposures have been estimated or calculated from these values. Since these calculations are fairly complicated, highly trained employees must be used and there is a possibility of errors being made; in high-production operations the time required for these calculations and for trial-and-error shots represent significant cost and time delay.

SUMMARY OF THE INVENTION Apparatus for automatically calculating various exposures for making halftone or similar types of images, is disclosed. Different exposures having different times are required in half-tone photography and the exposure times are calculated from the highlight density and the shadow density. The measurement of these factors and the computation for determining the particular exposure times is a complicated process and time consuming. The present invention utilizes shadow density and highlight density scales which have a number of discrete steps that are compared by an operator with the highlight and shadow portion of an image. The selection of particular shadow and highlight densities automatically controls the times for the various exposures without further computation by the operator.

Thus, after the operator has selected the highlight and shadow density values he may immediately proceed to make the exposures and produce the half-tone.

The operator does not have to make a reading and then set a dial or do any computation, in that the present apparatus automatically calculates the correct exposure times after the shadow and highlight density readings are made.

Since the control and timing units may be bulky, the highlight and shadow densities may be obtained with a small unit that may be connected to the main apparatus with a flexible cable or, in certain embodiments, may be inserted into the master unit after the highlight and shadow density settings have been made on the copy at a remote position.

Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the three units of the invention;

FIG. 2 is a front view of the master timer and a side view of the density setting unit;

FIG. 3 is a block diagram of the apparatus of this invention;

FIG. 4 is an electrical schematic of the invention with FIGS. 4a and 4b comprising the electrical schematic of the master timer and the control unit, and FIGS. 4c and 4d comprising the electrical schematics of the timing resistor selecting means of the evaluator;

FIG. 5 is a top view of the evaluator of the invention;

FIG. 6 is a sectional view of the evaluator; and

FIG. 7 is a sectional view taken at right angles of FIG. 6;

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates the photographic apparatus of this invention comprising a control unit 10 which is attached by a flexible electrical cable 11 to the master timer unit 12. An evaluator unit 13 may be set remotely and then inserted into an elec trical socket of the master timer unit 12. The units 12 and 13 have mating electrical sockets that may be engaged, but for purposes of illustration a cable 15 is shown connected between the units. The control unit 10 has a highlight switch 14, a main manual switch 16, a flash switch 17, a cancel switch 18 and a time-focus switch 19.

The end of the master timer unit 12 has a shutter output receptacle 2], a contactor output receptacle 22 and a flashlamp output receptacle 23. A flash intensity knob 24 has a pointer 26 which is readable against a numerical scale 25. A fuse 28 is also mounted in the end wall of the master timer unit 12.

The front panel 31 of the master timer unit 12 comprises an exposure unit 32 which has indicator wheels 33, 34, 35 and 36. A highlight exposure switch 37 may be set against indicia 38. Indicator lights 39, 40, 41, 42 and 43 indicate respectively, manual, highlight, main, flash and power. An onoff switch 44 and a time-focus switch 46 are also mounted on the front panel 31 of the master timer unit 12.

FIG. 3 is a block diagram of the apparatus of this invention. The evaluator or key 13 is set to the proper highlight and shadow densities and automatically establishes a switch setting on the highlight density switch 51 and an excess density range (EDR) on a printed circuit wiper switch 52. The switches 51 and 52 are respectively connected to a highlight-timing resistor bank 53 and an EDR-timing resistor bank 54, and the switches 51 and 52 select a particular one of these resistors. The EDR-timing resistor 54, selected by the particular setting of the switch 52, is connectable to a pulse generator 56 which produces an output to a firing circuit 57 which in turn is connected to an output relay 58. The output of the relay 58 is supplied to an intensity control 59 which has an output lead 61 that is connected to the flashlamp output receptacle 23. The timing resistor 54, which is selected by the EDR switch 52, determines the timing of the pulse generator 56 and thus the length of time that the firing circuit 57 is energized.

The highlight density switch 51 selects a particular timing highlight resistor 53 and supplies it to a contact 63 engageable by a movable switch 64. The switch 64 may also be moved to engage a contact 66 which is connected to a manual resistor 67. A pulse generator 68 is connected to the switch contact 64 and receives an input from a switch 69 that is movable between contacts 71 and 72 that are respectively connected to main manual capacitors 73 and highlight capacitors 74.

A pulse stretcher 76 receives the output of the pulse generator 68 and supplies an input to a predetermining counter 77 which also receives an input from a reset pulse stretcher 78. The predetermining counter also is connected to a manual setting 79. A firing circuit 81 is connected to the output of the predetermining counter 77 and also provides an output to a bistable flip-flop 82 which provides an output to pilot lamps 83. The flip-flop has a relay linkage 84 that connects it to the contact 69.

An output relay 86 is connected to the output of the flring circuit 81 and shutter receptacle 2] and contactor receptacle 22 are energized by the output relay 86.

FIGS. 5, 6 and 7 illustrate the evaluator 13. The unit has a baseplate 87 which is formed with a pair of windows 88 and 89, respectively, into which a shadow density scale 92 and a highlight density scale 91 are respectively receivable. For example, the shadow density scale 92 is formed with a plurality of windows 98 and the area surrounding the windows 98 becomes progressively darker from the top of the scale relative to FIG. 5, toward the bottom. Thus, if the density evaluator 13 is placed over a copy or similar original to be photographed, the darkest portion of the copy may be matched through one of the windows 98 with the area 99 adjacent to that particular window. A pointer 96 is slidably movable relative to the evaluator 13 and has a knob 97 for controlling it.

The highlight density scale 91 s formed with windows 93 and the area 94 surrounding the windows 93 becomes progressively darker from the top to the bottom, relative to FIG. 5, to allow the highlight density of a copy to be matched with one of the area 94 through a window 93. A pointer 101 is slidably mounted in the evaluator 13 and may be controlled by a knob 102.

A cover plate 103 is attached to the baseplate 87 by supporting standoff 104. The cover plate 103 is formed with a pair of slots 106 and 107, respectively, through which the shafts 108 and 109 extend. Shaft 108 carries knob 97' and shaft 109 carries knob 102. Shaft 108 carries the upper end 110 of pointer 96 and a guide pin 111 is attached to portion 110 and rides in a slot 112 in the cover plate 103. The shaft 108 passes through a slot 1 13 formed in a transverse link 114. The shaft then passes through a support plate 116 which is supported from the baseplate 87 by standoffs 117 and 118. A slot is formed in the support plate 1 16 and the shaft 108 has an enlarged portion 119 that rides in the beveled slot of plate 116. A channel guide 121 is connected to the plate 116 and guides a follower block 122 through which the shaft 108 extends. A spring 123 is mounted between the enlarged portion 119 and the follower block 122. Washers 124 and 126 are mounted about shaft 108 above and below, respectively, linkage 114. The shaft 109 and pointer 101 are mounted similarly to shaft 108 and the upper end of pointer 101 has a portion 127 through which the shaft 109 extends and has a guide pin 128 which is receivable in a slot 129 of the cover plate 103. The shaft 109 extends through the support plate 116 and has an enlarged portion 131 which is received in the beveled slot formed in the plate 116. A channel guide 132 is attached to the plate 116 and carries a guide block 133 through which the shaft 109 extends. A spring 134 is mounted between the enlarged portion 131 and the guide block 133. A wiper contact block 136 is attached to the lower end of shaft 109 and has a pair of wiper contacts 137 and 138 which engage tracks of a printed circuit board 139 mounted on suitable standoffs 141 and 142, respectively, from baseplate 87. A pin 143 extends through an opening formed in link 114 and through a slot 144 formed in the support plate 116. The lower end of pin 144 passes through a slot 146 formed in a linkage 147. The shaft 109 passes through a slot in link 114. The link 147 is formed with an opening 148 through which a pin 149 is received. Pin 149 is connected to a pivot block 151 which may be adjusted by a lead screw 152 that is threadedly received through the guide block 151. A knob 153 is mounted on the lead screw 152 to control the position of the pivot point of the link 147. The other end of link 147 is formed with a slot 154 through which a pin 156 is received. Pin 156 is mounted in a channel guide 157 that is attached to the lower surface of the support plate 116 and has a follower block 158 and a spring 159. A wiper contact 161 is formed with three wiper contacts 162, 163 and 164, respectively, for engaging associated contacts on the printed circuit board 139, and moves with pin 156.

The structure of the evaluator 13 allows the contacts 137 and 138 to be set to a highlight density corresponding to the setting of the pointer 101 against the highlight density scale On the other hand, the setting of the wiper contacts'162, 163 and 164 depend upon the settings of knobs 97 and 102 because the link 147 moves when both knobs 97 and 102 are moved. This may be observed by noting that with knob 102 stationary and knob 97 moving, the pin 143 will be moved through the link 114 to move the end of the linkage 147 and thus adjust the wiper contacts 162, 163 and 164. Alternatively, if the knob 97 is stationary and the knob 102 is moved, the link 114 will again move pin 143 in the slot 144, thus moving the linkage 147, and consequently the wiper contacts 162, 163 and 164. The position of the pivot pin 149 may be adjusted with the knob 153. This adjustment is made for particular conditions which exist with particular equipment and, once set for a particular set of conditions, remains fixed.

FIGS. 4:: and 4d illustrate the contacts 136 and 161, respectively. These wiper contacts move along printed circuit boards to selectively place different resistances in circuit for the timing device. The values of these resistors determine the particular times for the various exposures. For example, the end 138 of slide contact 136 is in continuous engagement with a printed circuit bus which is connected to an output terminal 171. The other end 137 of contact 136, engages contacts 172 which are respectively connected to resistors R,-R for example. The other end of the resistors R,R-, are connected to a bus 173 which connects to an output terminal 174. As shown in FIG. 40, the slide contact 161 has a center contact 163 which engages a bus conductor 176 which connects to an output terminal 177. The wiper contact 162 engages a plurality of terminals 178 which are connected to first ends, respectively, of resistors R -R The other sides of resistors R,,-R,,, are connected to a common terminal bus 179 which is connected to an output terminal 181. The wiper contact 164 engages a plurality of contacts 182 which are connected, respectively, to resistors R,,- R The other end of resistors R,,-R,, are connected to bus 179 and to output terminal 181. It is to be observed that the contacts 178 and 182 are staggered so that the resistors R,,R,,, and R ,-R, are alternately connected between the bus bar 176 and bus bar 179.

FIGS. 4a and 4b illustrate the master timer of this invention and it is to be noted that the resistors R,,R,, are connected across the terminals 177 and 181 which engage, respectively, the terminals 184 and 185 in the master timer unit. These resistors control the timing for the flash exposure.

The resistors R,R connect to terminals 186 and 187, respectively. These resistors control the timing for the main and bump exposures.

FIG. 4a and 4b illustrate the electrical schematic for the master timer unit 12. A power plug 190 is inserted into a suitable power supply and has a grounded terminal 191. One lead, 192, is connected to a fuse 193, and contacts of switches sW6A and SW6B-are respectively connected to the power leads. The switches SW6A and SW6A are linked together and are controlled by the toggle on-ofi' switch 44. A resistor R and power-on light 43 are connected across the switches SW6A and SW6B. A transformer T, has its primary connected across the switches SW6A and SW6B. The shutter and contactor plugs 21 and 22 are connected in parallel across leads 194 and 195 and have grounded contacts 196. A relay K, controls switches between relay contacts 1 and 9 and 4 and 12, respectively, in leads 197 and 198. The capacitor C11 is across contacts l(,, 1 and 9 and capacitor C, is across contacts K,, 4 and 12. AC power leads 197 and 198 also are connected to contacts 9 and 12 of relay K, which has contacts 1 and 4, respectively, that may be connected to contacts 9 and 12. A capacitor C,-, is connected across contacts 9 and l, and a capacitor C,, is connected across contacts 12 and 4. Flashlamp 42 and resistor R,,, are connected in series between contacts 1 and 4. A flash intensity potentiometer R is controlled by knob 24. Flashlamp plug 23 has a grounded lead 199 and power leads 201 and 202 that are respectively connected to contacts 4 of relay k and to the wiper contact on the potentiometer R The secondary of transformer T, is connected to a diode rectifier 202 which has one point grounded and the other point 203 connected to a capacitor C, which has its other side connected to ground. A lead 204 is connected from resistor 102 and to a capacitor C, which is across the switch SW5A. The resistor R, is connected to the switch SWSA and the capacitor C,, and the other side is connected to the gate of a SCR Q and to a resistor R which has its other side connected to ground. The cathode of the SCR is connected to ground. The anode of the SCR is connected to a resistor R,,, which has its other side connected to the relay K and a diode CR The other side of the relay and diode CR, are connected to lead 204. A resistor R is connected between resistor R and a capacitor C which has its other side connected to ground. A switch SW is connected across the resistor R and the capacitor C,,.

A diode CR is connected between the gate of SCR Q, and one side of resistor R, which has its other side connected to ground. A unijunction transistor 0,. has an electrode connected to the resistor R, and a diode CR Q also has an input electrode connected to the resistor R,,,,. The other side of resistor R is connected to terminal 185 and to a capacitor C, which has its other side connected to ground. Contact 6 of relay K, is also connected to contact 185, and contact of relay K is connected to resistor R, which has its other side connected to ground. Contact 184 is connected to contact 11 of relay K and contact 3 of relay K, is connected to wiper contact 206 of potentiometer R One end of potentiometer R is connected to resistor R,,,,, which has its other side connected to ground. The other side of potentiometer R, is connected to lead 207. Lead 207 is connected to resistor R which is connected to the third electrode of the semiconductor device 0,. Lead 207 is also connected to a potentiometer R which has its other side connected to a resistor R which has its other side connected to ground. A capacitor C, is connected across the potentiometer r,,, and resistor R A diode CR and zener diode VR, are connected in opposite polarity across the capacitor C,,,. A resistor R is connected between lead 204 and lead 207. A capacitor C and zener diode VR are connected in parallel between ground and lead 204. The wiper contact of potentiometer R, is connected to contact 3 of relay l(,. Contact 11 of relay K, is connected to contact 186. Potentiometer R is connected to contact 186 and has a wiper contact that connects to resistor R Switch SW,B has a moveable contact 210 for engaging a contact 211 that is connected to the other end of resistor R and a plurality of contacts which are connected electrically to lead 212 which is connected to contact 187. Contact 210 is connected to terminals 9, 10 and 11 of relay K and the moveable contact of the relay K is moveable to engage contacts 1, 2 and 3 or 5, 6 and 7 of the relay. A capacitor C, is connected from contacts 1, 2 and 3 of the relay K, to ground. Contacts 10 and 6 of relay K, are connected between capacitor C, and resistor R,,, which has its other side connected to ground.

Contacts 4 and 12 of relay K, are connected between resistor R which has its other side connected to ground and contacts 5, 6 and 7 of relay K Capacitors C C, and C, have first sides connected together and to contact 4 of relay K and the other sides connected to contacts of switch SWlE. The wiper contact of switch SWlE is connected to ground.

A unijunction transistor Q, has its emitter electrode connected to contact 210. The first base of the unijunction transistor 0, is connected to a resistor R,,, which has its other side connected to lead 207. A resistor R is connected between ground and the second base of the unijunction transistor 0,. A diode CR, is connected from the second base of Q, to the base of transistor 0,. A resistor R, is connected from the base of transistor O to ground. A resistor R, is connected from the base of the transistor 0 to the collector of a transistor 0,. The emitter of transistor 0, is connected to the base of transistor Q which has its emitter connected to ground. The collector of transistor Q is connected to a capacitor C, which has its other side connected to diode CR The base of the transistor 0 is connected to the diode CR The emitter of the transistor 0, is connected to ground. The

collector of transistor Q, is connected to a resistor R The second sides of resistors R,,,,, and R and R are connected together to a lead 215. The lead 215 is connected to a switch SW, which is connected in series with a switch SW,,. A lead 216 is connected from switch SW and resistor R to a connection point D. Lead 204 is connected to a connection point C and lead 215 is connected to a connection point E.

FIG. 4b illustrates connection points A, B, C, D and E. The countdown coil 217 of a preset counter 218 is connected across terminals A and B. A transistor 0, has its emitter connected to ground and its collector connected to a resistor R which has its other side connected to resistor R which has its other side connected to point E. A transistor Q, has its emitter connected to ground and its collector connected to a capacitor C, which has its other side connected to a diode CR which has its other side connected to the base of the transistor 0,. A resistor R is connected from the diode CR and the capacitor c, to the resistor R Point D is connected to the resistor R that has is other side connected to parallel combination of the diode CR and the reset coil 219 for the preset counter 218. Diode CR is connected from the diode CR, to the collector of transistor 0,. The transistor Q 9 has its emitter connected to the base of transistor 0 and its collector connected to a resistor R which has its other side connected to point C. A resistor R is connected from the base of the transistor 0,, to ground. A resistor R is connected from point C to a switch S, which is the final count output of the preset counter 218. A diode CR is connected to the switch S, and a resistor R is connected to the other side of the diode. The other side of the resistor R is connected to the base of the transistor Q, and to a resistor R which has its other side connected to ground. A switch SWSB is connected between resistor R and a capacitor C which is also connected to the diode CR Resistor R and resistor R are connected in series between ground and the other side of the capacitor C,.

A capacitor C and resistor R, are connected from resistor R to a junction point F. A resistor R and diode CR, are connected in series between the junction point F and the gate of an SCR Q Resistor R is connected from the gate of SCR, to ground. The cathode of SCR, is connected to ground. The anode of SCR is connected to resistor R which has its other side connected to the relay coil of relay K,. A diode CR is connected across the relay coil K,. The other side of the rely coil K, is connected to resistor R A capacitor C,,, and resistor R are connected in series between ground and the anode of SCR 0, and the resistor R,., is connected from resistor R to the base of a transistor Qn- The collector of transistor O is connected to lead 220 and the emitter of transistor 0,, is connected to indicator lights 39 and 41. The switch SWlA has a moveable contact 221 which engages contacts 223 and 222, respectively. The resistor R, is connected between indicator light 39 and contact 222, and the resistor R is connected between indicator light 41 and contact 223. The contact 221 is connected to a resistor R and the collectors of transistors Q and Q The emitter of transistor 0,, is connected to ground. The emitter of transistor 0,, is connected to the base of transistor Q The base of transistor 0,; is connected to the cathode of diode CR which is in series with a resistor R that has its other side connected to point F. A transistor Q, has its emitter connected to ground and its base connected to resistor R and a resistor R,,,. Transistor 0,, has its collector connected to the energizing coil of relay K, which has its other side connected to lead 220. A diode CR,, is connected in parallel with relay K, and a highlight indicator lamp 40 and resistor 51 are connected in series across the relay coil K A resistor R is connected from the collector of transistor 0,, to the base of a transistor 0,, A resistor R is connected from the base of transistor O1; to a switch SW2A. The other side of switch SW2A is connected to lead 220. A resistor R is connected from base of transistor 0,, to the switch SWSA. The other side of switch SWSA is connected to the moveable contact of switch SW 1C. Contacts 230 of switch SWlC are connected to lead 220.

In operation, the toggle switch 44 is moved to on" position closing switches SW6A and SW6B. This supplies a pulse to the power supply which turns SCR Q,, on. This pulse is differentiated by capacitor C,, resistor R,,,,, resistor R and diode CR,,, a resistor R This energizes relay K, which opens contacts 1 and 9 and 4 and 12. Relay K,, when energized, closes contacts 6 and 10 providing a discharge path for any residual voltage on timing capacitor C Relay K, also opens contacts 3 and 11, disconnecting the power supply from the timing network. The electronic circuitry has been cocked with these operations.

It is to be realized, of course, that a suitable shutter and light source energizer has been connected to the shutter plug 21 and the contactor plug 22. For main exposure, the switch 16 is depressed. This closes switch SW2B which turns off SCR Q Switch SW28 is mechanically linked to switch SWZA and is simultaneously depressed. Switch SW2A places transistors 0, and 0, of the flip-flop, which they form a part, in the on" state and turns off transistor 0, This holds transistors Q, and Q, in the on state.

When switches SW2A and SW2B are released, relay K, becomes deenergized and transistor Q,, turns on light 41. Contacts 9, 1 and 12, 4; and 3, ll of relay K, close when the relay K, is deenergized. Contacts 10, 6 of relay K, simultaneously open. This supplies power to the contactor plug 22 and the shutter plug 21, and the shutter and the lights for the main exposure will be turned on.

The capacitor C will charge to peak firing voltage of transistor Q, through the selected resistor R,R,. When the transistor 0, fires, a pulse is created at resistor 11,, which turns on transistors Q and O, which pulls in the coil 217 of the preset counter. The count coil is held in until the capacitor C charges through resistor R to turn on transistor 0,, which turns off transistors Q, and 0,.

The preceding process is repeated until the latching relay of the preset counter turns to zero. The latching relay is preset. A standard Hecon counter is used. Such units are commercially available and only the count coil, reset coil and final-count output are illustrated in the drawings.

When the end of the count is reached to which the counter has been preset, the switch S closes applying base voltage turning on transistors and Q which turns off transistor Q, and pulls in reset coil 219 resetting the counter back to the predetermined setting. Reset current is released when capacitor C charges through resistor R, to turn transistor 0 back on and to turn transistors Q, and 0,, off. Switch 8,, also creates pulses through capacitor C,,, resistors R and R diode CR and resistor R which turns on SCR 0, This again energizes relay K, opening the associated contacts of relay K, which were closed when the relay was deenergized.

When the voltage at the SCR drops to holding voltage, (about one-half volt), the transistor 0,, will be turned off which turns indicator light 41 off. This completes the main automatic exposure.

For the highlight exposure, switch 14 is depressed which corresponds to switches SW3A and SW38 on the electrical schematic. Switch SW3A, when depressed, turns on transistor 0,, through resistor 38 thus turning light 40 on and energizing relay K When relay K, is energized, contacts 9, 10 and 11 are connected, respectively, to contacts 5, 6 and 7, connecting one of the three capacitors C C and C, in circuit, which has been selected by switch SWIE that is controlled by knob 37 and which selects the percentage of highlight. The relay contacts 4 and 12 are opened removing the discharge path from the selected capacitors C C and C Simultaneously, switch SW38 opens relay K, and the remaining operation for the highlight exposure is similar to that explained above when the main exposure is being made, except the time will be a percentage of the main exposure due to the placing of the highlight capacitors C C or C in the circuit.

In manual position, however, zero percent highlight, switches SWlD, SWIC AND SWlE all provide open circuits and no highlight exposure can occur.

In manual position, the predetermined setting of the Hecon counter controls the timing. The timer will work without the computer resistors R,-R-, inserted. The pulse repetition rate of transistor 0, and its timing network R and R and capacitor C is fixed at 10 hertz which provides an accuracy of onetenth second as indicated on the counter dial 32.

For flash exposure, switch 17 is depressed which corresponds to switch SW,,. This turns SCR 0 off, and deenergizes relay K Contact 11 is connected to contact 3 of relay K and contacts 10 and 6 are opened removing the discharge path. Capacitor C charges to the peak point firing voltage of unijunction transistor 0, through the selected EDR resistors R R Resistor R limits the current through the unijunction transistor 0,. As transistor Q, fires, a pulse is created across resistor R,, which is applied to the gate of SCR Q through diode CR across resistor R,,,,. SCR 0,, fires, energizing relay K;,. The relaxation oscillator fires only once during the timing interval. When contacts 9, l, 12 and 4 of relay K are closed during the timing interval, power is applied to light 42 and to leads 201 and 202 which is connected to the flash lamps (not shown). The potentiometer R allows the intensity of the lamps to be adjusted.

Thus, it is seen that the evaluator illustrated in detail in FIGS. 5, 6 and 7, after setting the BDR adjustment, may be placed over a copy to be photographed and pointer 96 set to read the shadow density and the evaluator will then be moved and pointer 101 set to read the highlight density. This will move the slide contacts 161 and 136, respectively, so that a pair of resistance values will be chosen depending upon the particular position of the contacts 136 and 161. This will be supplied through leads and 173 through terminals 186 and 187, illustrated in FIG. 4a of the master timer. The resistance values selected by slide contact 161 will be fed by leads 176 and 179 to contacts 184 and 185 in FIG. 4a. It is to be realized that the resistors may be mounted on the printed circuit board which the contactors 137 and 164 or 162 are in engagement, or they might alternatively be mounted within the master timer and a connection made between the evaluator unit and the master timer so as to choose a particular resistance value. Thus, the invention allows the evaluator, which may be compact, to be moved about to make evaluations of the highlight and shadow densities. It is tobe particularly noted that the resistor R,R-, is directly chosen by the slide contact 136. However, the slide contact 161 is positioned depending upon the motion of both knobs 97 and 102. This is because the resistance value across the slide contact 161 is the excess density range which is calculated from the highlight density and shadow density settings. This is the purpose for the various linkages in the evaluator illustrated in detail in FIGS. 5, 6 and 7.

Although minor modifications might be suggested by those versed in the art, it should be understood that we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.

We claim as our invention:

1. A computer for automatically calculating exposure time in photography comprising an evaluator for evaluating an image to be produced and including a pair of evaluator means that may be set respectively to the highlight and shadow densities of the image to be reproduced, highlight-density-timing means controlled by said first of said pair of evaluator means, excess-density-range-timing means controlled by the setting of said first and second of said pair of evaluator means, and a master timer connected to said first and second timing means to calculate the main, flash and bump exposures for a camera utilized in half-tone process photography.

2. A computer according to claim 1 comprising a housing, said pair of evaluator means mounted in said housing and movable relative to said housing, and said pair of evaluator means including a pair of highlight and shadow density scales for evaluating the image to be reproduced.

3. A computer for automatically calculating exposure times in photography comprising an evaluator for evaluating an image to be reproduced and having a pair of indicia that may be set to the highlight and shadow densities of the image to be reproduced and said evaluator produces a first output indicative of the highlight density based on the setting of the first indicia, and said evaluator produces a second output resulting from the settings of said pair of indicia, said evaluator including a housing, said pair of indicia movable mounted relative to said housing, a pair of highlight and shadow density scales associated with said pair of indicia, said evaluator including a support member formed with slots formed within said housing, said pair of indicia movably mounted in two of the slots of said support member, a first link connected to said pair of indicia and moveable therewith, a second link with one end moveable in a third slot of said support member, a pivot pin connecting the first and second links and extending into a fourth slot of the support member, and a master timer associated with said evaluator and controlled by the set condition of said evaluator to calculate exposure times for reproducing said image.

4. A computer according to claim 3 wherein said evaluator comprises a first wiper contact moveable with said first link, a second wiper contact moveable with the second link, and first and second switch portions engageable with the first and second wiper contacts, respectively.

5. A computer according to claim 4 comprising a plurality of highlight density resistors connected to said first switch portion, and a plurality of excess density resistors connected to said second switch portion.

6. A computer for automatically calculating exposure times in photography comprising an evaluator for evaluating an image to be reproduced and having a pair of indicia that may be set to the highlight and shadow densities of the image to be reproduced and said evaluator produces a first output indicative of the highlight density based on the setting of the first indicia, and said evaluator produces a second output resulting from the settings of said pair of indicia, said evaluator including a housing, said pair of indicia movably mounted relative to said housing, a pair of highlight and shadow density scales associated with said pair of indicia, said evaluator including a pair of arms indicative of the highlight density range and the excess density range respectively mounted in said housing,

and a master timer associated with said evaluator and controlled by the set condition of said evaluator to calculate exposure times for reproducing said image.

7. A computer according to claim 6 wherein the first arm is moveable with the first indicia, and the second arm is moveable with both indicia.

8. A computer according to claim 6 wherein said master timer comprises a first timing circuit which is controlled by a first set condition of said evaluator and comprises a first pulse generator which has an output controlled by said first set condition and a first firing circuit connected to said pulse genera tor.

9. A computer according to claim 8 wherein said first pulse generator is a relaxation oscillator.

10. A computer according to claim 8 wherein the set condition of said evaluator establishes the value of an impedance connected to said first timing circuit which controls its timing cycle.

11. A computer according to claim 6 wherein said master timer comprises a second timing circuit which is controlled by a second set condition of said evaluator and comprises a second pulse generator which has an output controlled by said second set condition, a preset counter connected to said second pulse generator, and a second firing circuit connected to the preset counter.

12. A computer according to claim 11 wherein the second set condition of said evaluator establishes the value of an impedance connected to said second timing circuit which controls its timing cycle.

13. A computer according to claim 12 comprising means for varying the timing cycle of said second timin circuit.

14. A computer for automatically calcu atmg mam, flash and bump exposure times in half-tone process photography comprising: an evaluator for evaluating an image to be reproduced and settable for various conditions; a main control unit including a master timer controlled by the set condition of said evaluator and said evaluator connectable to said main control unit; and, said evaluator having a pair of moveable means that may be set respectively to the highlight and shadow densities of said image, and the setting of said scales determining various exposure times in said main control unit. 

1. A computer for automatically calculating exposure time in photography comprising an evaluator for evaluating an image to be produced and including a pair of evaluator means that may be set respectively to the highlight and shadow densities of the image to be reproduced, highlight-density-timing means controlled by said first of said pair of evaluator means, excess-density-rangetiming means controlled by the setting of said first and second of said pair of evaluator means, and a master timer connected to said first and second timing means to calculate the main, flash and bump exposures for a camera utilized in half-tone process photography.
 2. A computer according to claim 1 comprising a housing, said pair of evaluator means mounted in said housing and movable relative to said housing, and said pair of evaluator means including a pair of highlight and shadow density scales for evaluating the image to be reproduced.
 3. A computer for automatically calculating exposure times in photography comprising an evaluator for evaluating an image to be reproduced and having a pair of indicia that may be set to the highlight and shadow densities of the image to be reproduced and said evaluator produces a first output indicative of the highlight density based on the setting of the first indicia, and said evaluator produces a second output resulting from the settings of said pair of indicia, said evaluator including a housing, said pair of indicia movable mounted relative to said housing, a pair of highlight and shadow density scales associated with said pair of indicia, said evaluator including a support member formed with slots formed within said housing, said pair of indicia movably mounted in two of the slots of said support member, a first link connected to said pair of indicia and moveable therewith, a second link with one end moveable in a third slot of said support member, a pivot pin connecting the first and second links and extending into a fourth slot of the support member, and a master timer associated with said evaluator and controlled by the set condition of said evaluator to calculate exposure times for reproducing said image.
 4. A computer according to claim 3 wherein said evaluator comprises a first wiper contact moveable with said first link, a second wiper contact moveable with the second link, and first and second switch portions engageable with the first and secoNd wiper contacts, respectively.
 5. A computer according to claim 4 comprising a plurality of highlight density resistors connected to said first switch portion, and a plurality of excess density resistors connected to said second switch portion.
 6. A computer for automatically calculating exposure times in photography comprising an evaluator for evaluating an image to be reproduced and having a pair of indicia that may be set to the highlight and shadow densities of the image to be reproduced and said evaluator produces a first output indicative of the highlight density based on the setting of the first indicia, and said evaluator produces a second output resulting from the settings of said pair of indicia, said evaluator including a housing, said pair of indicia movably mounted relative to said housing, a pair of highlight and shadow density scales associated with said pair of indicia, said evaluator including a pair of arms indicative of the highlight density range and the excess density range respectively mounted in said housing, and a master timer associated with said evaluator and controlled by the set condition of said evaluator to calculate exposure times for reproducing said image.
 7. A computer according to claim 6 wherein the first arm is moveable with the first indicia, and the second arm is moveable with both indicia.
 8. A computer according to claim 6 wherein said master timer comprises a first timing circuit which is controlled by a first set condition of said evaluator and comprises a first pulse generator which has an output controlled by said first set condition and a first firing circuit connected to said pulse generator.
 9. A computer according to claim 8 wherein said first pulse generator is a relaxation oscillator.
 10. A computer according to claim 8 wherein the set condition of said evaluator establishes the value of an impedance connected to said first timing circuit which controls its timing cycle.
 11. A computer according to claim 6 wherein said master timer comprises a second timing circuit which is controlled by a second set condition of said evaluator and comprises a second pulse generator which has an output controlled by said second set condition, a preset counter connected to said second pulse generator, and a second firing circuit connected to the preset counter.
 12. A computer according to claim 11 wherein the second set condition of said evaluator establishes the value of an impedance connected to said second timing circuit which controls its timing cycle.
 13. A computer according to claim 12 comprising means for varying the timing cycle of said second timing circuit.
 14. A computer for automatically calculating main, flash and bump exposure times in half-tone process photography comprising: an evaluator for evaluating an image to be reproduced and settable for various conditions; a main control unit including a master timer controlled by the set condition of said evaluator and said evaluator connectable to said main control unit; and, said evaluator having a pair of moveable means that may be set respectively to the highlight and shadow densities of said image, and the setting of said scales determining various exposure times in said main control unit. 